Chlorothalonil is a broad-spectrum protective phthalonitrile fungicide developed and launched by Diamond Shamrock (USA, later merged into ISAGRO and other companies) in the 1960s.
Mode of Action:
Chlorothalonil is classified as Group M5 by the Fungicide Resistance Action Committee (FRAC) and acts as a multi-site inhibitor. It reacts with various sulfhydryl (-SH) containing enzymes (such as glyceraldehyde-3-phosphate dehydrogenase) within pathogenic fungal cells, destroying enzyme activity and interfering with normal cellular metabolism and energy production, leading to fungal death. Due to its multiple sites of action, it is extremely difficult for pathogens to develop resistance.
Target Diseases and Application Scope:
Applicable Crops: Vegetables (such as tomatoes and cucumbers), fruit trees, peanuts, potatoes, turfgrass, and ornamental plants.
Controlled Diseases: Shows excellent efficacy against various diseases caused by Ascomycetes, Basidiomycetes, Deuteromycetes, and Oomycetes, such as potato late blight, tomato early blight, peanut leaf spot, fruit tree anthracnose, downy mildew, and various leaf spots.
Characteristics: A purely protective fungicide with no systemic translocation; application must ensure uniform coverage on both the upper and lower surfaces of leaves. It has a long residual period and strong rainfastness. It is often mixed with systemic fungicides (such as metalaxyl or azoxystrobin) to provide both immediate protection and long-lasting curative effects. It is highly toxic to fish and is prohibited in aquaculture areas.
Main Formulations:
Chlorothalonil 40% SC